The -50 is just an updated version with a slighty different control pack (I think the -50 was in reference to Warn's 50th anniversery.) You can't go wrong with that winch. Just make sure it works and you should be good to go!
I have an 07 6.0 and so far (knock on wood) it has been great. I was pretty gun shy about the platform but most of the problems are preventable with proper care. I only have about 41k on mine now but its been heads and tails more reliable at this point than my 99 Dodge was with the CTD...